strength." Besides, each cell is strengthened at its mouth by a strong thread formed of a mixture of wax and propolis, soldered to the inner edges, and giving it, by filling up the angles, a circular form. This gives great solidity to the fabric, and prevents the mouths of the cells from being easily injured by the unceasing ingress and egress of the bees.
It is remarkable that the cell of a honey-comb, including its hexagonal sides and its pyramidal basis, is the figure, of all others, the best adapted for containing the greatest possible quantity, in the least possible space, and with the least expense of material. "There are only three possible figures of the cells," says Dr. Reid, "which can make them all equal and similar without any useless interstices. These are the equilateral triangle, the square, and the regular hexagon." Of these, the hexagon is the best fitted for the bee-cell, for it unites to the requisites stated by Dr. Reid, economy of material, and a figure better adapted to the shape of the insect. This last property would have been possessed in a greater degree by the cylindrical form, but it would have left a vacant space between every three contiguous cells. The square and the triangle would have left no interstices, but would have consumed more wax, and been ill-adapted to the shape of the bee. The hexagonal form employed combines all the requisites; for, together with a convenient figure for the reception of the body of the insect, it secures economy of material and economy of space, both as respects the number of
